The present invention relates generally to electrical adapters for mobile phones, portable notebook computers and associated chargers, and more particularly to electrical adapters having both a retractable cable assembly that is used to store corresponding cables in a convenient manner, and an electrical plug assembly for use with various types of electrical outlets.
A wide variety of electrical devices typically draw AC power from a commercial source, usually delivered through a wall receptacle or socket, but require that this AC power be converted into one or more DC voltages for powering these devices. Electrical adapters have been used extensively throughout the world to provide such DC voltages to these electrical devices.
A common disadvantage of prior art electrical adapters is that they are conventionally equipped with a cable long enough to accommodate the expected distance between a power source such as a wall plug and the expected position of the device to be powered. In practice, however, the device is often much closer to the power source than the adapter manufacturer expects. As a result, the excess cabling is often allowed to lie or hang loose and become intertwined with other cabling. This is at best unsightly and at worst a source of electrical problems.
Consequently, what is desired is a means for storing the cables of an electrical adapter efficiently and conveniently, including means that would be feasible especially in situations where the adapter is used while traveling, or in situations where portability of the electrical device being powered by the adapter is essential. What is needed is a suitably small ergonomic means for retracting the cables, thereby allowing the cables to be selectively stored when not required by the user. It would be ideal if the cables could be stored and retrieved, as a user desires. This would allow a consumer to selectively extend or shorten the cabling of the electrical adapter on an as-needed basis depending upon the circumstances and application.
Retractable cable assemblies are one solution to the problem of selectively extending and shortening the cabling ergonomically. For example, retractable cable assemblies are commonly used for the AC cord on a vacuum cleaner. However, in such applications, there are few size constraints on the retraction mechanism. Additionally, retractable cables are often used for the cable connecting earphones to a personal stereo. These conventional retractable cable assemblies, while providing convenient cable handling, are inadequate for addressing the challenges faced with those electrical devices in the nature of a notebook computer or mobile phone. The challenge that the inventors of the present invention face concern electrical adapters for electrical devices that include cables carrying significantly more current (e.g., 2-5 Amps) than a cable for an earphone and require a heavier gauge wire which is less flexible and therefore difficult to retract. Because size is critical for the electrical adapter of the present invention, the conventional retractable mechanisms for storage of cables of vacuum cleaners and stereo earphones are ill-suited. What is therefore needed is a retractable cable assembly that is part of an electrical adapter that provides a compact manner for storing a low voltage cable, which may require heavy copper in the wire for a given adapter power rating.
Because many electrical devices are sold for use throughout the world, and because a world standard for electrical power requirements is lacking for the operation of these electrical devices, it would be highly desirable to provide an electrical adapter that is not only portable, but is able to accommodate various electrical plug assemblies, which may include a high voltage plug and converter circuitry, used in different parts of the world. Where the electrical devices are notebook computers and mobile phones used with electrical adapters that have electrical plugs inserted into an electrical receptacle, it would be beneficial if the electrical adapter is suitable for use with several countries"" electrical plug requirements. With people traveling worldwide, it is unpredictable for the consumer to know which particular type of receptacle will be employed in a destination country. To carry several adapters and adapter prongs while traveling and to anticipate a particular country""s electrical prong being used is not only logistically cumbersome, but also a burden, as multiple parts become easily lost.
Conventionally, the converters within the electrical adapters are designed to receive a range of voltage inputs so that only a single adapter need be carried. But, in order to comply with various outlets that deliver AC power around the world, consumers typically carry a variety of input cords, each with a different type of plug. Moreover, there are commercially available electrical adapters sold for the purpose of accommodating travelers, and which are mechanical assemblies having on one end an electric plug, and on the other end, a socket accepting the standard plug interengageable with a particular country""s type of receptacle. However, the parts required for these options are very bulky and can be heavy. Although these conventional electrical adapters permit the conversion of one type of electrical energy to another type, and fulfill their respective particular objectives and requirements, they do not disclose an adapter with a retractable cable assembly and interchangeable electrical plug assembly for use with a mobile phone, portable personal computer and their corresponding chargers that overcome all of the above-mentioned drawbacks.
FIGS. 1-3 illustrate the above-mentioned disadvantages of the prior art which the present invention is designed to overcome. Specifically, FIG. 1 is a perspective view of an exemplary prior art electrical adapter having a long cable. Typically, when a consumer first purchases electrical adapter 10 from the manufacturer, it arrives with the electrical cable 12 bundled and tied with a wire-twist 16 as shown. Cable 12 is coupled to a plug 14 for connection with the electrical device (not shown). Removing the wire-twist allows the cable to be used in an extended fashion over its entire length. As is seen, cable 12 is a low voltage cable for carrying the DC voltage to the mobile electrical device, which may be a portable personal computer (e.g. notebook), mobile phone, or a corresponding electrical charger that requires operation from an AC power source. Although not shown in FIG. 1, electrical adapter 10 includes a converter for converting the AC power to a DC output voltage.
As shown in the perspective view of FIG. 2, electrical adapter 10 is further coupled to a high voltage cable 16, for conventionally carrying the AC power from a conventional AC power outlet, via a receptacle plug 18 shaped to enable insertion into the AC power socket. Similarly with respect to cable 12, a user upon purchasing the electrical adapter typically finds cable 16 tied with a wire-twist from the manufacturer. With use however, these cables 12, 16 become tangled and twisted, thereby making the electrical adapter 10 logistically awkward as a unit to use, as seen in FIG. 2. This is especially true when the electrical adapter is used for providing power to a portable personal computer having a variety of attachments each requiring a separate cable attached to the port of the computer and to the peripheral devices. The multiple cables generally become tangled and interfere with use of the electrical device. For example, a portable computer powered using the electrical adapter situated at a desk with many other peripheral devices attached thereto in close proximity to a wall-mounted electrical receptacle may have many wires in a tangled state.
Additionally, a problem with the conventional electrical adapter 10 is that the cables 12, 16 are often wound around the unit by hand and stored loosely as shown in FIG. 2. This is highly undesirable since it may result in the cables unraveling and the unit becoming bulky, thereby being especially cumbersome when the electrical adapter is put into a briefcase. Excessive wear and tear of the cables may also be experienced as a result. Depending upon the patience of the consumer, the cables may be tied together to prevent unraveling, usually with a wire-twist, rubber band, tie-wrap or string.
The retractable cable assemblies of the prior art often comprise a retractor having a base subassembly supporting a reel. FIG. 3 shows a partially-exploded perspective view of a retractor 30 of the prior art having a base subassembly 32 rotatably supporting reel 34 thereabout. Reel 34 is operable to rotatably wind and unwind a cable 36 by means of a torsion spring coil 38 that is biased in a predetermined direction. Although not shown, the retractor 30 is commonly controlled to selectively preclude rotation of the reel 34 relative to the subassembly 32 by frictionally engaging and locking the reel.
A drawback with such conventional retractors is that they include circular electrical contacts 39 disposed along the center portion of the cable reel 34. This results in a larger area being required to implement the electrical contact between the cable and circuitry of the electrical adapter. Another problem with this embodiment is that it results in greater friction being exerted on the cables and their electrical contact points. This is highly undesirable since it may result in accelerated wear-and-tear of the connections and components, thereby leading to earlier degradation of the retractor. Such degradation leads to the integrity of the electrical contacts being compromised. Moreover, the structure of the circular contacts 39 in the conventional retractor, such as that shown in FIG. 3, substantially increases the cost and complexity of manufacturing. Consequently, the objective of the invention as described below is an improved retractor that provides the benefits of minimizing the size of the electromechanical components, of reducing the friction between the cable and the electrical contacts occurring during rotation of the reel, and of providing a cost-effective manner of fabrication. Another objective of the invention is the inclusion of ergonomic features that aid the consumer in selectively extending and retracting a cable manually, obviating the need for an automatic retraction mechanism, such as a torsion spring coil as in the retractor of FIG. 3.
Consequently, it would be advantageous if a consumer could use a single electrical adapter with the storage functions desired herein, in an interchangeable manner so as to accommodate various types of electrical receptacles, and with a size of the conventional AC/DC adapter package being considerably reduced by restructuring the cable storage and packaging criteria. Furthermore, it would be beneficial if such an electrical adapter included ergonomic features that aided the consumer in selectively extending and retracting a cable manually.
The present invention is directed towards an electrical adapter having a manually retractable cable assembly for a low voltage cable, where the electrical contacts of the retractable cable assembly are disposed along an axis of rotation to minimize the friction between the cable and contacts therein when the cable is selectively extended and retracted. The electrical contacts of the present invention enable constant electrical conduction between components when the cable is extended from and retracted into the retractable cable assembly.
Broadly stated, the present invention provides an electrical adapter, comprising a housing; an electrical plug assembly supported by the housing, the assembly including an interchangeable module coupled to an adapter module, the interchangeable module having a plurality of prongs for receiving a first voltage when mated with an electrical receptacle, and a converter electrically coupled to the assembly and for converting the first voltage into a second voltage; and a retractable cable assembly supported by the housing and electrically coupled to the converter, the retractable cable assembly including a cable coupled at one end to an electrical plug for outputting the second voltage, a reel for winding and unwinding the cable, the reel being rotatably supported by the housing, a wheel for enabling the cable to be manually dispensed from and retracted into the housing; a pair of first contacts electrically coupled to each other, one of the first contacts being coupled to another end of the cable, supported by the reel and rotatable about the other of the first contacts, a pair of second contacts electrically coupled to each other, one of the second contacts being coupled to the another end of the cable, supported by the reel and rotatable about the other of the second contacts, and a pair of terminals electrically coupled respectively to the other of the first contacts and the other of the second contacts for receiving the second voltage from the converter. For the present invention, the wheel is preferably mounted to the reel.
These and other objects of the present invention will become apparent to those skilled in the art from the following detailed description of the invention and embodiments, the accompanying drawings, specification, and claims.